Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 231005
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
505 AM EST TUE DEC 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.

TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.

TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014

FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.

FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.

ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.

ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.

LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014

DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING NORTHEAST TOWARDS THE
AREA. THERE WILL LIKELY BE TWO SURGES OF PRECIPITATION WITH THIS
LOW...THE FIRST COMING DURING THE OVERNIGHT HOURS AND THE SECOND
ARRIVING BY LATE MORNING OR EARLY AFTERNOON. THE SECOND WAVE WILL
PRODUCE THE HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014

LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
     FOR MIZ001>007-009>011-084-085.

  WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
     FOR MIZ012>014.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA







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